The oldest record of barrel vaults is estimated to date back to 4000 BC. These provided the spans in the Sumerian ziggurat at Nippur in Babylonia, built from fired bricks amalgamated with clay mortar. This type of vault was built as a continuous round arch and became a characteristic architectural element of Roman architecture, later used also in Renaissance architecture.
_Maureen_M._Evans.jpg?1646840531 "© Maureen M. Evans")
